# Strain Control and Layer-Resolved Switching of Negative Capacitance in BaTiO$_3$/SrTiO$_3$ Superlattices

## TL;DR

This study uses atomistic simulations to show how epitaxial strain can control negative capacitance in BaTiO$_3$/SrTiO$_3$ superlattices, including layer-specific switching, with implications for capacitor technology.

## Contribution

It introduces a novel prediction of layer-resolved negative capacitance switching driven by strain in superlattices, enhancing understanding of ferroelectric multilayer behavior.

## Key findings

- Epitaxial strain tunes negative capacitance over a broad temperature range.
- Negative capacitance can switch between layers at low temperatures.
- Multidomain transition behavior improves superlattice capacitance applications.

## Abstract

Negative capacitance in BaTiO$_3$/SrTiO$_3$ superlattices is investigated by Monte Carlo simulations in an atomistic effective Hamiltonian model, using fluctuation formulas for responses to the local macroscopic field that incorporates depolarizing fields. We show epitaxial strain can tune the negative capacitance of the BaTiO$_3$ ferroelectric layer and the overall capacitance of the system over a broad temperature range. In addition, we predict and explain an original switching of the negative capacitance from the BaTiO$_3$ layer to the SrTiO$_3$ layer at low temperatures for intermediate strains. Our results indicate how the diffusive character of the multidomain transition in these superlattices improves their viability for capacitance applications.